1. Field of the Invention
This invention relates to a rotor for a hammer mill and the like and, more particularly, to a hammer for a hammer mill used to grind, shred or fluff various materials such as cereal grains, tobacco and wood pulp.
2. Description of the Prior Art
In the grinding of cereal grains, for example, in a hammer mill, the primary grinding takes place when the grain is driven against a breaker plate. The grain is actually caused to be driven against the breaker plate by means of the rotating hammers. The hammers also drive the grain against a screen where the final reduction takes place through the striking of the grain by the hammers. The size of the reduced grain which is discharged from the mill is determined by the diameter of the perforations in the screen.
In prior art hammer mills, the hammers were generally rigid, metallic members of various fixed shapes which were detachably secured to a rotor or the like. In one particular known construction, in addition to a rotor shaft, hammers and bearings, the rotor structure also included retainer discs, hinge pins, spacers and collars. These additional members not only added to the expense and complexity of the structure but, in particular, it is known that the WK.sup.2 (mass moment of inertia times the acceleration of gravity) of the structure was relatively high and, therefore energy consuming. Also, it is known that energy losses due to friction generally and, in particular, to air pumping by the retainer discs was inherent in this type of structure. Moreover, it was frequently necessary when changing to a different feed stock, to replace all the hammers with hammers of a particular shape or design suitable for the stock being worked on and having a length giving a particularly desired hammer to screen clearance. It is, accordingly, a desideratum of this invention to eliminate or substantially reduce the foregoing constraints of the prior art structure.